Analgesic efficacy of selective tibial nerve block versus partial local infiltration analgesia for posterior pain after total knee arthroplasty: a randomized, controlled, triple-blinded trial.

BACKGROUND: The adductor canal block provides pain relief on the anterior aspect of the knee after arthroplasty. Pain on the posterior aspect may be treated either by partial local infiltration analgesia of the posterior capsule or by a tibial nerve block. This randomized, controlled, triple-blinded trial tests the hypothesis that a tibial nerve block would provide superior analgesia compared to posterior capsule infiltration in patients scheduled for total knee arthroplasty under spinal anesthesia with an adductor canal block. METHODS: Sixty patients were randomized to receive either infiltration of the posterior capsule by the surgeon with ropivacaine 0.2%, 25 mL, or a tibial nerve block with 10 mL of ropivacaine 0.5%. Sham injections were performed to guarantee proper blinding. The primary outcome was intravenous morphine consumption at 24 h. Secondary outcomes included intravenous morphine consumption, pain scores at rest and on movement, and different functional outcomes, measured at up to 48 h. When necessary, longitudinal analyses were performed with a mixed-effects linear model. RESULTS: The median (interquartile range) of cumulative intravenous morphine consumption at 24 h was 12 mg (4-16) and 8 mg (2-14) in patients having the infiltration or the tibial nerve block respectively (p = 0.20). Our longitudinal model showed a significant interaction between group and time in favor of the tibial nerve block (p = 0.015). No significant differences were present between groups in the other above-mentioned secondary outcomes. CONCLUSION: A tibial nerve block does not provide superior analgesia when compared to infiltration. However, a tibial nerve block might be associated with a slower increase in morphine consumption over time.

A randomised controlled trial of intravenous dexmedetomidine added to dexamethasone for arthroscopic rotator cuff repair and duration of interscalene block.

Prolongation of peripheral nerve blockade by intravenous dexamethasone may be extended by intravenous dexmedetomidine. We randomly allocated 122 participants who had intravenous dexamethasone 0.15 mg.kg-1 before interscalene brachial plexus block for day-case arthroscopic rotator cuff repair to intravenous saline (62 participants) or intravenous dexmedetomidine 1 µg.kg-1 (60 participants). The primary outcome was time from block to first oral morphine intake during the first 48 postoperative hours. Fifty-nine participants reported taking oral morphine, 25/62 after placebo and 34/60 after dexmedetomidine, p = 0.10. The time to morphine intake was shorter after dexmedetomidine, hazard ratio (95%CI) 1.68 (1.00-2.82), p = 0.049. Median (IQR [range]) morphine doses were 0 (0-12.5 [0-50]) mg after control vs. 10 (0-30 [0-50]) after dexmedetomidine, a difference (95%CI) of 7 (0-10) mg, p = 0.056. There was no effect of dexmedetomidine on pain at rest or on movement. Intra-operative hypotension was recorded for 27/62 and 50/60 participants after placebo vs. dexmedetomidine, respectively, p < 0.001. Other outcomes were similar, including durations of sensory and motor block. In conclusion, dexmedetomidine shortened the time to oral morphine consumption after interscalene block combined with dexamethasone and caused intra-operative hypotension.

Regional analgesia for lower leg trauma and the risk of acute compartment syndrome: Guideline from the Association of Anaesthetists.

Pain resulting from lower leg injuries and consequent surgery can be severe. There is a range of opinion on the use of regional analgesia and its capacity to obscure the symptoms and signs of acute compartment syndrome. We offer a multi-professional, consensus opinion based on an objective review of case reports and case series. The available literature suggested that the use of neuraxial or peripheral regional techniques that result in dense blocks of long duration that significantly exceed the duration of surgery should be avoided. The literature review also suggested that single-shot or continuous peripheral nerve blocks using lower concentrations of local anaesthetic drugs without adjuncts are not associated with delays in diagnosis provided post-injury and postoperative surveillance is appropriate and effective. Post-injury and postoperative ward observations and surveillance should be able to identify the signs and symptoms of acute compartment syndrome. These observations should be made at set frequencies by healthcare staff trained in the pathology and recognition of acute compartment syndrome. The use of objective scoring charts is recommended by the Working Party. Where possible, patients at risk of acute compartment syndrome should be given a full explanation of the choice of analgesic techniques and should provide verbal consent to their chosen technique, which should be documented. Although the patient has the right to refuse any form of treatment, such as the analgesic technique offered or the surgical procedure proposed, neither the surgeon nor the anaesthetist has the right to veto a treatment recommended by the other.